Apathy

I think it depends on intent. In my opinion, the reason you'd get a projector is because you want to generate a true in-home movie viewing experience where you restrict virtually all light to maximize the projector's capabilities and put in a sound system. Projectors are not good for potentially well-lit areas or if you want it to use it to host gameday parties because, inevitably, you're going to have light saturation. (You'll also have a continual cost with them since you need to replace bulbs).

The 4K TV doesn't have the same issues, is more versatile, and you can get really good one nowadays without spending $2,000.

tl;dr if you're building an in-home theater, get a projector. Otherwise, get the 4K tv.

As of right now I have a Sony 65” 4K 900e tv with 5 speakers and 2 dual SVS PB2000 subwoofers with 4 Micca M8’s in-ceiling rear speakers on the way. 

If I went the projector route, I’d look at getting a 120” screen. My basement is 30’x16’ with 8’ ceilings so I’ll have the space to do it. Just want to weigh my options first and get thoughts from others

@Enhance has the right of it. It really boils down to what your intention is for the space. People will want to come watch game days on that size of screen. I have the lighting controls in two banks. One for behind the seating and one in front. It allows for some light for parties but also total darkness for movie theater experience. I've got an SVS sub as well. It's the size of a coffee table. It literally rumbles the house. I say get what you want to use the room for and enjoy.